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T. G. MARTIN.

MEAsuREn sERvlcE TELEPHoNE SYSTEM.

APPLICATION FILED OCT. 24. IIJIB I, 9 1I 93, T 69 Patented Aug. 1, 1916.

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T. MARTIN.

MEASURED SERVICE TELEPHONE SYSTEM.

` APPLlCATlON HLED OCT. 24| 1913. l 1L 93., Il 69. Patented Aug. 1, 1916.

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T. G. MARTIN.

MEASURED SERVICE TELEPHONE SYSTEM.

APPLICATION FILED oc. 24. 1913.

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TALBOT G. MARTIN, F CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, 0F CHICAGO, ILLINOIS, A. CORPORATION OF ILLINOIS.

MEASURED-SERVICE TELEPHONE SYSTEM.

Speccaton of Letters Patent.

Ilatented Au g. I, 1916.

To all whom 'it may concern Be it known that I, TALBOT Cr. MARTIN, a citizen of the United States of America, and resident of Chicago, Cook county, Illinois, have invented certain new and useful Improvements in Measured-Service Telephone Systems, of which the following is a specification.

My invention relates to measured service telephone systems in which each subscribers line is provided with a meter for registering the number of calls made by that line. Heretofore, in such systems, it has been customary to have such meter controlled by a change in direction of the current in the line.

The object of my invention, however, is to provide a meter which is operated by a change in the strength of the current rather than by any change in the direction of the same. Heretofore an attempt has been made to operate the meter by changing the current in this manner, but in such systems it .was necessary for the switches by which the connection was established to be operated by a weak current, and then when the current was returned to normal strength the meter was operated. By my present invention, however, the switches are operated by a current of normal strength, and then when the connection is established the current is first decreased and then returned to normal strength, and this variation in the strength of the current causes the operation of the meter magnet.

My invention will be more readily understood by reference to the accompanying drawings, in which I have illustrated the I same in connection with an automatic system of a well-known type.

Figures l, 2 and 3 taken together show a complete circuit connection established between a calling substation A (Fig. l) and a called substation A (Fig. in a system embodying the principles of my invention. Fig. 1 shows an automatic substation A, individual first selector switch C and second selector switch D. At F a meter is shown which is for the purpose of registering the number of calls made by the subscriber at substation A. Fig. 2 shows a connector switch E. Fig. 3 shows selector switch C and a substation A.

Unlike the usual type of automatic telephone systems, the system herein represented is without the so-called individual line switch. The lines from the substation A terminate in a first selector switch C. The banks of said selector switches are multiplied with banks of other first selector switches of the same group, said group usually consisting of one hundred switches. The trunks leading from the different levels of the banks of said ,first selector switches terminate in second selector switches l). These switches are also in groups, the trunks leading from the different levels of the banks terminating in connector switches E.

The automatic substation A (Fig. l) comprises the usual receiver 2, .transmitter 3, ringer -l and condenser 5. Being an automatic substation it is also provided with an impulse-sending mechanism for controlling the automatic switches, which mechanism is represented diagrammatically by a pair of impulse springs G and 7 and an impulse wheel 8, which latter may be controlled in a well-'known manner through the medium of a dial provided with finger holes in such a way that the impulse springs may be momentarily separated Ya number of times corresponding to the respective digits of the number of the called subscriber. Associated with the lines of the substation A there is a call-registering device F, which is controlled by the coil 65.

The first selector switch C is of the same general type of selector switch disclosed in United States Letters Patent No. 815,321, granted March 13, 1906, to Keith, Erickson and Erickson, the circuits, however, being modified to adapt the switch to be controlled by impulses delivered over two sides of a line circuit in series. Among other details, the selector C comprises a bank of contacts arranged in horizontal rows or levels, which are adapted to be engaged by a set of wipers 10, l1 and 12 carried upon a shaft (not shown) which has a vertical movement controlled by the vertical magnet 13 and a rotary motion controlled by the rotary magnet 14. The selector is also provided with a side switch comprising` the wipers 2, 28 and .29 controlled in the usual and well-known.manner by the private magnet 30. The operations of the switch are controlled by the subscriber through the medium of the double-wound line relay l5. The side switch is restored to normal Vposition by means of the release magnet 16, which, upon. energizing, withdraws the retaining pawls from the shaft. The springcontacts 17 and 18 are permitted to close and the springs 68 and 76 to open only when the switch shaft has been raised one or more steps from its lowest position. The relays 20, 55, 66 and 21 are slow actingthat is, they denergize slowly after their energizing circuits have been broken. The second selector D is somewhat similar to the irst selector C. Y

The connector switch E (Fig. 2) is of the same general type of connector switch disclosed in United States Letters Patent No. 815,176, granted March 13, 1906, to Keith, Erickson and Erickson, the circuits, however, being modiied to adapt the switch to be controlled by impulses delivered over the two sides of a line in series. Like the selectors, the connector is provided with a shaft (not shown) which is controlled by a vertical magnet 25 and a rotary magnet 26. The usual side switch comprising the wipers 31, 32, 33, 34 and 35 is controlled by the private vmagnet 36 in the usual and wellknown manner. The magnet 37 is the usual release magnet. The connector also comprises the usual line relay 38, back-bridge relay 30, busy locking relay 40, ringing relay 41 and the slow acting relays 42, 43 and 44. The relay 45 is of a high resistance and is placed in series with the line relay 38 after the call has been completed by means of the side switch wiper 33 passing to third position, and is short-circuited by the operation of the back-bridge relay 30 when the called subscriber answers. The first selector C and substation A are the same as the first selector lC and substation A,`respectively, in Fig. 1.

A general description of the apparatus having been given, it will now be explained how a connection may be established between a calling substation A and a called substation A', the number of which latter we will assume to be 2220. Upon the removal of the receiver at the calling substation A preparatory to making a call, a circuit is closed through the line relay 15 of the selector switch C. This circuit extends from ground G through the lower winding of the relay 15, springs 46 and 47, relay 48, conductor 49, springs 51 and 50, impulse springs 7 and 6, receiver 2, transmitter 3, conductor 52, springs 53 and 54 and the upper winding of the relay 15 to battery B, thence through battery B to ground G. As a result of closing this circuit the relays 15 and 48 energize in series. The relay 15, upon energizing, closes a circuit through the slow acting relay55, said circuit extending from ground G2 through the springs 56 and 57 and the relay 55 to battery B. The relay 55, upon energizing, prepares a circuit for the vertical magnet by closing the springs 58 and 59, and also opens the circuit of the release magnet at the springs 58 and 60. The relay 48, upon energizing, closes an energizing circuit for the slow acting relay 66. This circuit extends from ground G5 through the sprin 74 and 75, o normal springs 68 and 76 and the relay 66 to battery. The relay 66, upon energizing, closes a circuit for itself at the springs 78 and 77 and also opens the circuit of the relay 65 at the springs 63 and 64.

The apparatus is now in readiness for the operation of the dial for the first digit ot the called number The dial at the calling substation, upon being operated for the first digit 2 of the called number, momentarily opens the line circuit twice at the impulse springs 6 and 7. This breaking oi the line circuit twice at the springs 6 and 7 allows the line relay 15 to deenergize twice, thereby closing a circuit through the vel'- tical magnet 13 of the selector switch (l twice. This circuit extends from ground (i2 through the springs 56 and 67, 58 and 50, slow acting relay 2l, vertical magnet 13 and the side switch wiper 27 to battery B thence through battery B to ground G. The vertical magnet 13, as a. result ol ener` gizing twice over the circuit just traced, operates to advance the switch shaft and wipers two steps to a position opposite the second row or level o1z bank contacts, and at the same time the shaft-controlled springs 17 and 18 are closed and the springs 68 and 76 are opened. The relay 55, the circuit ot which was momentarily broken by the decnergization of the relay 15, does not deenergize during these momentary interruptions of its circuit and thereby keeps the circuit to the vertical magnet closed, and also retains the circuit oi the release magnet 16 open at the springs 58 and 60. The slow acting relay 21, which was included in the circuit with the vertical magnet, is energized and, being slow acting, remains energized while the impulses arfe being delirered. In its energized position the relay 21 closes a circuit through the private inagnet 30. The relay 21 deenergizes a'lter the impulses have been transmitted, thus allow ing the private magnet to also deinergize, which in turn allows the side switch wipers to pass to second position in the usual and well-known manner. The side switch wiper 27, upon passing to second positiomswitches the battery lead from the vertical magnet 13 to the rotary magnet 14.. A circuit is thereby closed extending from ground G through the rotary interrupter springs 60, rotary magnet 13, slow acting relay 20 and the side switch wiper 27 to battery B. The rotary magnet, upon energizing, rotates the wipers one step onto the lirst bank contact of the second level and also 'opens its own circuit at the springs 69. The operation or the rotary armature also closes the circuit ot the private magnet 30, said circuit extending from ground G3 through the spring 70, armature 71 and the private magnet 30 to battery B. The private magnet energizes over this circuit, but if the lirst bank contact is idle, it again deencrgizes, when the rotary magnet falls back, thereby allowing the side switch wipers to pass to third position. It the first contact is busy, however, the private magnet remains energized over a circuit extending` from the grounded private wiper 11 through the side switch wiper 29 (in second position) and the private magnet 30 to battery B. The side switch wipers are thus held in second position and the rotary armature is again attracted and the shaft wipers are rotated one more step onto the second bank contacts. Thus it will be seen that the rotary magnet acts in a manner similar to that of a buzzer to rotate the shaft wipers onto an idle bank contact, at which time the pr. fate magnet deenergizes and permits the side switch wipers to pass to third position. The relay 20, which was included in the circuit with the rotary magnet, energizes and remains energized during the rotation of, and for a moment after, the side switch wipers have passed to third position, whereby a guarding potential is placed on the private wiper 11 previous to the operation of the relays ot the second selector D. The wiper 27, upon passing to third position, connects battery to the relay 65, but the circuit of this relay is still open at the springs G3 and G4. The side switch wiper 2S, upon passing to third position, closes an energizing circuit through the line-switching relay 72 of the selector C. This circuit extends from ground G4 through thc springs G1 and G2, side switch wiper 28 and the relay 72 to battery B. A guarding ground is also placed on the private bank contacts oit the calling line in the banks of all the connectors that have access to said line. The relay 72, uponenergizing, disconnects the linei'elay 15 from the line and extends the line connection over the heavy conductors shown and through the wipers 10 and 12 to the second selector D. The line relay S0 of the switch D thereupon becomes energized and closes the circuit of the relay S1, which in turn, upon energizing, completes a circuit extending from ground G through the springs 83 and S4, conductor S2, wiper 11, side switch wiper 29 of the switch C, springs 35 and S0 and the relay to battery B. rThis circuit maintains the relay 55 energized after its original energizing circuit is broken by the relay 15, which` deenergizes when it is disconnected from the line. The relay S1 also maintains a guarding ground potential upon the private bank contacts of the trunk line in the banks ot the first selector switches C which have access thereto.

When the substation calling device is operated for the second digit 2, the selector D operates in practically the same manner as explained for the selector C to extend the connection over the trunk conductors 87, 88 and 89 to the connector E (Fig. 2). The line relay 38 of the connector thereupon becomes energized and closes the circuit of the relay 42. This circuit extends from ground G7 through the springs 91 and 92, relay 42 and the springs 93, 94, 95 and 9G to battery B. The relay 42, upon energizing, places a holding ground on the relay 81 of the selector D. This holding circuit for the relay 81 now ex tends from ground G8 through the side switch wiper 3l, springs 97 and 98, conductor S9, side switch wiper 99, springs and 101 and the relay 81 to battery B. The energization of the relay 42 also prepares a circuit ior the vertical magnet and opens the circuit of the release magnet, as described in connection with the selector C.

lVhen the substation calling device is operated for the third digit 2, the circuit of the line relay 3S of the connector is momentarily broken twice. Since the relay 42 is slow acting it does not de'energize during the momentary interruptions of its circuit by the relay 38, so that each time the latter relay is denergized, a circuit is closed extending' from ground G7 through the springs 91 and 90, 103 and 102, relay 43, vertical magnet 25 and the wiper 32 to battery B. The vertical magnet 25 receives two impulses over this circuit and operates to raise the switch wipers 22, 23 and 24 to a position opposite the second level of bank contacts. The relay 43, which was included in series with the vertical magnet, remains in its e11- ergized position during' the entire time impulses are being transmitted through it and operates to close the circuit of the private magnet 36. This circuit extends from ground GD through the springs 104 and 105 and the private magnet 36 to battery B. After the last impulse has been delivered, the relay 43 de'energizes and opens the circuit of the private magnet 36, which in turn deenergizes and allows the side switch to pass from lirst to second position. The movement of the side switch wiper 32 from iirst to second position transfers the battery connection from the vertical magnet to the rotary magnet 20. The calling subscriber now operates his calling device for the last digit 0, in response to which the connector line relay 38 operates to transmit ten impulses through the rotary magnet, in series with the relay 43, whereby the shaft wipers are rotated ten steps onto the contacts of the desired line. The relay 43 operates in response to this digit in the same manner as for the previous digit to cause the private magnet 3G to advance the side switch one more step-that is, from second to third extends position. By the engagement of the side switch wiper 34 with its third-position contact, the line is extended through to the called substation, as shown by the heavy conductors. The side switch wiper 85, in passing to third position, places a ground on the private bank contacts of the called line in the banks of all the connectors that have access to said line, and also closes aeireuit through the line-switching relay 106 of the called selector C. The relay 10G operates to disconnect the line relay 107 from the line and to complete the connection from the calling line through to the called line. By passing to third position the side switch wiper 31 switches the ground connection for the slow acting relay 81 of the switch D from ground GS to ground G7 through the springs of the line relay 38. The side switch wiper 32, in passing to third position, closes a circuit through the ringing relay 41. This circuit extends from ground G10 through the interrupter 10S, springs 109 and 110, relay 41 and the side switch wiper 32 tO battery B. The ringing relay is intermittentlyk energized through the medium of the interrupter 10S and each time disconnects the calling line from the called line and bridges the ringing current generator 111 across the called line to signal the called subscriber.

The side switch wiper 33, upon passing to third position, transfers the ground connection of the calling line from ground G11 to ground G12, thus putting the high resistance relay 45 in series with the line relay 38. This resistance added to the line allows the relay 48 (Fig. 1) to fall back, which in turn opens the circuit of the slow acting relay (36 to permit it to denergize.

Upon the response of the called subscriber his line is provided with talking current through the windings of the backbridge relay 30 of the connector switch, which relay, upon energizing, opens the contact of springs and 9G, thereby transferring the battery connection for the holding relay 42 from said springs to and through the relay 44 by removing the short-circuit from around said relay. The relay 44. thereupon encrgizes and opens the springs 93 and 94, which prevents the relay 44 from deenergizing should the called subscriber hang up his receiver, and also opens the circuit of the ringing relay 41 at the springs 109 and 110. The operation of the back-bridge relay 40 also short-circuits the high resistance relay 45 by placing direct ground battery onto the third-position contact of the side switch wiper' 33. This ground potential from ground ,G13 through the springs 113 and 112, 114 and 115 to the wiper 33. rIhe high resistance relay 45, upon being thus short-circuited, permits the relay 48 (Fig. 1)V to again energize. rl`he operation of the relay .l-S at this time closes a circuit through the meter magnet 05. rl`his circuit extends from ground G through the springs 74 and 75, springs 03 and 04- (which arenow in engagement), thence through the magnet (35 and the wiper 27 to battery B. The meter magnet, upon energizing, operates the meter to register the call and to also close a locking circuit for itself extending from ground G through the magnet springs and 117, magnet 05 and the wiper 27 to battery. The locking of the meter in this manner prerents the called subscriber from registering more than one call by the continuous operation of his receiver suf'itch-hook. It will be noticed that the relay 4S is able to energize the n'ieter magnet 05 at this stage, because the side switch wiper 27 of the iirst selector is in third position and the oil-normal springs 68 and 7G are open. li the springs 0S and 70 were not separated, the relay (30 would again energize and open the circuit of the magnet After the conversation is completed., the release of the connection is brought about by the hanging up of the receiver at the calling substation in the following manner: lhen the receiver' at the substation A is restored to the switch-hook, the separation of the switch-hook springs 50 and :'11 opens the circuit of the line relay 38 of the connector. The relay 38 thereupon deenergizes to open the circuit of the relays 42 and 14. The relay 42, upon denergizing, closes a circuit through the release magnet 37, said circuit extending from ground G7 through the springs 91 and 90, springs 103 and 11S, magnet 37 and the oil-normal springs 119 and to battery B. The magnet 37, upon energizing, restores the switch shaft and side switch wipers to normal position. rlhe circuit of its own release magnet is broken, when the shaft reaches its lowest position, by the separation of the oil-normal springs 119 and 120. The falling back of the relay 42 also disconnects the holding grouml for the relay S1 of the selector D. 'lhe relay 81, upon deifnergizing, closes a circuit through the release magnet 125. This circuit extends from ground G15 through the springs 121 and 123, 121 and 122, magnet 125 and the springs 127 and 120 to battery B. The magnet 125, upon energizing, operates to release the shaft and shaft wipers in the same manner as described above to restore the same to normal position. Like the connector, the selector release circuit is broken when the shaft reaches its lowest position.

The relay 81, upon falling back. breaks the circuit of the relay 55 of the selector C. The relay 55 denergizes and causes the release of the selector C just as explained for the selector D. The side switch wiper 27, upon being restored to normal position, opens the circuit of the magnet 65. rIhus all the apparatus is put in readiness for another' call.

It having been explained how a connec` tion `is established and registered with an idle line, it will now be explained how a connection may be prevented from being made with a busy line. If the line upon which the connector shaft wipers come to rest is busy, the private wiper 23 will tind a guarding potential upon the private bank contact and a circuit will then be completed through the relay l0. rIhis circuit extends from said ground at the private bank contact through the wiper 35 (in second position) and the relay l0 to battery B. The relay l0, upon energizing, opens the circuit of the rotary magnet at the springs 128 and 129 and forms a locking circuit for itself extending from ground G8 through side switch wiper 31, springs 97 and 98, 132 and 133, relay l0 and the private magnet 3G to battery Il. rlhe private magnet remains energized and opens the line to the called substation. The engagement of the springs 130 and 131 of the relay l() places a busy signal from the busy signaling machine M upon the line et the calling subscriber. The calling subscriber, upon hearing the busy signal, hangs up his receiver, thereby releasing the appa atus in the manner described above.

In telephone systems employing service meters on the subscribers lines for registering the calls made, it is often desirable to provide .means whereby the calling subscriber will not be charged for certain calls, such as those in which he calls attendants or operators at the central oliice to ask for information, long distance connections, etc. Provision for such free calls may be very easily made in the system shown herein. It will be remembered that the operation of the meter is dependent upon the current in the calling line first being strong enough to operate the relay 48, then being reduced sulliciently to allow said relay to fall back, and then being brought back to a sufficient value to cause said relay to pull up again. ril'iere'lore, in order to allow any lines to be called tree, it is only necessary to make such lines accessible by connector switches in which the lower winding oi the line relay S8 is connected permanently to ground so that no resistance corresponding to the relay l5 is introduced into the circuit when the side switch of the connector passes to third position. lWhen a call is made through such a connector as this, the relay 66 (Fig. 1) is .not permitted to dee'nergize, and, furthermore, the current in the calling line is in no wise affected when the call is answered, and accordingly the meter magnet G5 will not be operated.

It will accordingly be seen that I khave devised a mezsured service system in which the switches are operated by a current of normal strength and in which the meter `magnet is operated by first varying the strength of this current and then returning the same to normal.

While I have illustrated and described my invention in connection with a particular type oi" automatic telephone system, in which automatic switches of a well-known type are employed, it will, of course, be understood that if desired other trunking arrangements could be employed, such as the insertion of the well-known line switches and secondary switches, and that the selectors and connectors employed could be of any of the well-known types.

What I claim as my invention is 1. In a telephone system, a plurality of subscribers lines, means including automatic switches for establishing connection between two of said lines, a meter for the calling line, means for supplying current of normal strength to operate said switches and to supply talking current to said lines, and means controlled by lowering the strength of said current for operating saidI meter.

2, In a telephone system, a plurality of subscribers lines, means including automatic switches for establishing connection between two of said lines, a meter for the calling line, means for supplying current 'for operating said switches, and means for reducing the strength of said current and then returning the same to normal for controlling the operation of said meter.

3. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a meter for the calling line, means for supplying current for operating purposes, means for reducing said current when said connection is established and means for returning Vthe same to normal upon the response oi the called subscriber, and means controlled by the reduction and by the increase for opera ting said meter.

4. In a. telephone system, a plurality of subscribers lines, means including automatic switches for establishing connection between two of said lines, a meter for the calling line, means for supplying current for operating purposes, means for reducing said current when said connection is established and 'for returning the same to normal upon the response ot' the called subscriber, and means controlled thereby for opera-ting said meter.

5. In a telephone system, a subscribers line, a meter provided with an operating magnet associated with said line, a relay controlling the circuit of said operating magnet, and means controlled by the said relay first energizing and then denergizing and again energizing for initially closing the circuit of said operating magnet.

6. In a telephone system, a plurality of subscribers lines, means including automatic Y of operating current adapted to be connected switches :tor establishing connection between two of said lines, a meter magnet associated with Vthe calling line, a relay controlling the circuit of said meter magnet, and means for energizing and then denergizing and again energizing said relay to initially close the circuit of said meter magnet. Y

7. In a telephone system, a. plurality of subscribers lines, means for Vestablishing connection between two of said lines, a source to a callingline, a meter provided with an operating magnet associated with the calling gse line, a relay included in series with said calling line for controlling the operation oi' said meter, said relay beine' adapted to be operatedby said 'operating current, means tor Y two of said lines, meter provided with an operating magnet associated with the calling line, a relay included in said line, means for supplying ope 'ating current to said line through said relay for controlling the operation of said switches, said relay being operated-by said operating current, means 'tor reducing the current passing through said re- Y lay when said connection is established with theA called line to permit said relay to become inoperative, means for returning the current to normalwhen the called subscriber responds, whereby said-relay is again operated,-and means controlled by the successive operations of said relay for closing the circuit o said operating magnet.

9. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a service meter provided with an operating magnet associated with the calling line, means for supplying current for operating purposes, means for varying the strength of said current 'in both sides of the line in series upon the Vcompletion of said connection, means for thereafter returning Vsaid current to normal constant strength, and means cony trolled thereby for causing the operation of said operating magnet.

10. In a telephone-system, a -pluralitylof subscribers lines, means including automatic switches for establishing connection between'two of said lines, a service meter associated withy the calling line, an operating magnet for said meter, means for supply- Ying current for operating said switches,

means for Vautomatically varying the strength of said current when said connection is established, means lor thereafter returning said current to normal strength, and means controlled thereby for controlling the operation of said operating magnet.

l1. In a telephone system, a suns-cribers line, a meter provided with an operating magnet associated with said line, a relay controlling the circuit or said operating magnet, means controlled by the said relay iii-st energizing and then deinergizing and again energizing for initially closing the circuit oit said operating magnet, and a locking circuit for said operating magnet ior maintaining the same energized.

l2. ln a telephone system, a plurality ole subscribers lines, means including automatic switches for establishing connection between two ol said lines, a meter magnet associated with the calling line, a relay controlling the circuit oi said meter magnet, means for energizing and then deiuergizing and again energizing said relay to initially close the circuit of said meter magnet, and a locking circuit for said meter magnet -lior maintaining tlie same energized.

13. In a telephone system, a plurality of subscribers lines, means :lor establishing connection between two olE said lines, a source oit operating current adapted to be connected to a calling line, a meter provided with an operating magnet associated with the calling line, a relay included iu series with said calling line 'for controlling the operation of said meter, said relay being adapted to be operated by said operating current, means for automatic; lly decreasing the flow of current through said relay when connection between the two lines is completed to permit said relay to become inoperative, means for thereafter returning said current to normal strength to again operate said relay, means controlled by said relay or closing the circuit of said operating magnet, and means controlled by the energization of said operating magnet to close a shunt circuit about said relay.

ll. ln a telephone system, a plurality ol subscribers lines, means including automatic switches for establishing connection between two oit said lilies, a meter provided with an operating magnet associated with the calling line, a relay included in said line, means for supplying operating current to said line through said relay for controlling the operation of said switches, said relay being operated by said operating magnet, means for reducing the current passing through said relay when said connection is established with the called line to permit said relay to become inoperative, means for rcturning the current to normal when the called subscriber responds, whereby said relay is again operated, means controlled by the successive operations of said relay for l) fi lili closing the circuit of said operating magnet, and means controlled by the energization of said operating magnet to close a shunt circuit about said relay.

15. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a service meter associated with a calling line, an operating magnet therefor, a circuit for said magnet having a pair of normally open contacts controlled by a relay, a pair of normally closed contacts controlled by a second relay individual to the line, means for energizing both of said relays when a subscriber initiates a call, and means for maintaining said second relay energized until the call is completed.

lf3. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a service meter associated with a calling line', an operating magnet therefor, a relay included in said calling' line, a second relay, a circuit for said operating magnet having normally open contacts controlled by said first relay and normally closed contacts controlled by said second relay, means for energizing both of said relays when a subscriber initiates a call, and means for maintaining said second relay energized until a connection with a called line has been established.

17. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a serv* ice meter associated with a calling line, an

operating magnet therefor, a circuit for said magnet having a pair of normally open contacts controlled by a relay, a pair of normally closed contacts controlled by a second relay, means for energizing both of said relays when a subscriber initiates a call, a locking circuit for said second relay controlled by said first relay, said second relay being slow acting to prevent the same from deinergizing during the momentary denergizations of said first relay while a call is being established,means for denergizing said first relay when a call is established to thereby de'linergize said second relay, and means for thereafter energizing said first relay v. ithout energizing said second .relay to thereby close the circuit of said operating magnet.

18. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a service meter associated with a calling line, an operating magnet therefor, a relay included in said calling line, a second relay, a circuit for said operating magnet having normally open contacts controlled by said first relay and normally closed contacts controlled by said second relay, means for energizing both of said relays when a subscriber initiates a call, a locking circuit for said second relay controlled by said first relay, said second relay being slow acting to prevent the same from denergizing during the momentary denergizations of said first relay while a call is being established, means for denergizing said first relay when a call is established to thereby denergize said second relay, and means for thereafter energizing said first relay without energizing' said second relay to thereby close the circuit of said operating magnet.

19. In a telephone system, a subscribers line, a selector switch therefor, a side switch for said selector having three operative positions, a service meter associated with said line, an operating magnet therefor, a circuit for said operating magnet having a normally open contact controlled by said side switch and adapted to be closed when said side switch is in third position, normally closed contacts in said circuit controlled by a relay, normally open contacts in said circuit controlled by a second relay, and means for energizing said second relay after the switch has operated and said first relay is denergized to thereby close the circuit of said operating magnet.

20. In a telephone system, a subscribers line, a service meter associated with said line, an operating magnet for said meter, a circuit for said magnet including normally closed contacts controlled by a first relay and normally open contacts controlled by a second relay, means for energizing said second relay when the subscriber initiates a call, an initial energizing circuit controlled by saidsecond relay for energizing said first relay, a locking circuit for said first relay for maintaining said first relay energized to thereby maintain the circuit of said magnet open until a call is completed, and means for then denergizing said first relay and energizing said second relay to thereby close the circuit of said operating magnet.

2l. In a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a service meter associated with a calling line, an operating magnet therefor, a circuit for said magnet having a pair of normally open contacts controlled by a relay, a pair of normally closed contacts controlled by a second relay, means for energizing both of said relays when a subscriber initiates a call, a locking circuit for said second relay controlled by said first relay, said second relay being slow acting to prevent vthe same from deenergizing during the momentary deenergizations of said first relay while a call is being established, means for deenergizing said'first relay when a call is established to thereby denergize said second relay, means for thereafter energizing said first relay without energizing thereby close the circuit of said operating said second relay tov open contacts controlled by said` first relay a andfnornia'lly closed contacts controlled by .Y as

eratingfma'gnet.

.said second relay, means for energizing both of said relays when a subscriber initiates a call, a locking ciicuit for said second relay controlled by said first relay,` said second relay being slow acting to prevent the saine from denergizing duringV the momentary denergizations or' said irstrelay while a call yis being established,means for vde'e'nergizing said iirst jrelaywhen a call is established to thereby deenergize said second relay, ineans for thereafter energizing said iii-st relay without` energizing said second relay to thereby Vclose the circuit of said operating magnet, and'means controlled by the'energization of v'said operating magnet to close a shunt circuit about said iii-st relay.

23. in a telephone system, a plurality ci subscribers lines, means including automatic selecting and connecting switches toi' establishing` connectiongbetween two of said lines, a meter for the calling, line, means for supplying `current y for operating said switches, means inV said connector for reducing the strength of said operating currentwhen said connector establishes connection with a called line, meansfor thereafter returning said current to normal strength, and means controlled by said variation in the current for controlling the operation of said meter.

` 2li. ln a telephone system, a plurality of subscribers lines, means including an automatic connector switch for establishing connection between two of said lines, a meter providedV with an operating magnet Vassociatedwith the calling line, a relay included in saidv line, means for supplying operating layl being adapted'tobecome inoperative on said reduced current,'means for returning said operating current to normal strength when the ycalled subscriber responds, whereby said relay is Vgain operated, and means controlled by the successive operations of saidrelay for closing the circuit of said op- 25. In a telephone system, a plurality of subscribers lines, -means including auto-V maticpselecting and connectingjswitches for establishing connection between two of said lines, a meter provided with an operating magnet associated with the calling line, a relay included in said line, means for supplying operating current to said line through said relay, said relay being adapted to be operated by said operating current, a high resistance relay in said connector adapted to bev included in circuit with said operating current when said connector establishes connection to a called line to thereby reduce the strength of said current and render said irst relay inoperative, means for short-circuiting said high resistance relay upon the response of the called subscriber to again render said lirst relay operative, and means controlled by the successive operations of said first relay for closing the circuit of said operating magnet.

26. In a telephone system, a plurality of subscribers lines, means including automatic selecting and connecting switches for establishing connection between two of said lines, a meter provided with an operating magnet associated with the calling line, a relay included in said line, means for supplying opcratin g current to said line through said relay, said relay being adapted to be operated by said operating current, a high resistance relay in said connector adapted to be included in circuitwith said operating current when said connector establishes connection to a called line to thereby reduce the strength or' said current and render said iirst relay inoperative, means for short-circuiti'ng said high resistance relay upon the response oil the called subscriber to again render said iirst relay operative, means controlled by the successive operations of said iirst relay for closing the circuit oi" said operating magnet, and a shunt circuit for said irst relay controlled by said operating inagnet.

27. In a telephone system, a plurality of subscribers lines, means including automatic selecting and connecting switches for establishing connection between two oi said lines, a meter provided with an operating magnet associated with the calling line, a relay included in said line, means for supplying operating current to said line through said relay,rsaid relay being adapted to be operated by said operating current, a high resistance relay in said connector adapted to be included in circuit with said operating current when said connector establishes connection to a called line to thereby reduce the strength oit said current and render said iii-st relay inoperative, means for short-circuiting said high resistance relay upon the response of the called subscriber to again render said iirst relay operative, means controlled by the successive operations ot said lirst relay for closing the circuit of said operating magnet, a shunt circuit for said first relay controlled by said operating magnet, and a looking circuit for said meter magnet for maintaining the same energized.

28. ln a telephone system, a plurality of subscribers lines, means for establishing connection between two of said lines, a meter for the calling line, means for supplying current for operating purposes, Vmeans for reducing said Current when said Connection is established and for returning the same to normal constant strength, said means under the control of the Called subscriber, and means controlled by the reduction of said current for operating the meter.

29. Tn a telephone system, a Calling line, a called line, means for connecting the two, a central source of current for operating Copies purposes, means for supplying a steady current to the line for talking purposes, a meter for the calling` line, and means for reducing Z0 said current whereby said meter may be subsequently operated from the called line.

30. In a telephone system, a calling,- line and a called line, automatic means for conneoting the two, a central source of Current for operating and talking` purposes, a meter for the Calling line, and means for reducing the current for operating` said meter.

Signed by me at Chicago, Cook count Tllinois, this 15th day of October, 1913.

TALBOT G. MARTIN.

`Witness`es G. YANG oHowsKI, RAY STOKELY.

of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents,

Washington, D. C. 

